RMR battery life in subzero temperatures

[MWAG19919]

I recently started carrying an RMR-equipped G19, and I had a concern. If I have to repeatedly leave the gun+optic in the car overnight in subzero temperatures, will the battery life be dramatically affected? Let’s assume normal brightness (setting 5 or 6) and quality battery (Duracell, Energizer, Sony).

A little background: I work in a hospital, which in IL is a GFZ. I wear scrubs, so “concealed is concealed” doesn’t apply even if I wanted to be a felon. So, I have to leave my EDC in the car overnight 3x a week. It seems that every year we get a week or so of temps close to or below 0 F. I plan to change RMR batteries yearly on my birthday, but would carrying it to work during those brutal winter weeks cause the battery to die sooner than 1 year?

(Bonus question, will it affect my X300 battery life as well?)

[Wake27]

Not sure about your specific question, but I had to replace my battery yesterday so just as an FYI, mine jumps between the second and third highest settings (6 & 7 I think?) depending on what I'm doing and I'm getting a pretty consistent eight months of use.

[mack7.62]

Assuming you are using lithium batteries you should be OK, they are rated to 40 below and work much better in cold temps than alkaline batteries.